Table 1.

Studies reporting reference limits for CSF Aβ42 and T-tau in healthy people.

Author	Setting	Sample size	Age	Sex	Diagnostic criteria for healthy individuals	Statistics	Reference limits
Sjögren et al. (2001)	Norwegian University Norwegian Hospital	231 (total) 175 (age >50 years)	61.3 ± 18 (mean age ± SD) 21–93 (range)	177 F 54 M	No symptoms or signs of psychiatric or neurological disorders: People aged ≥60 years: MMSE score = 28–30 People aged <60 years: no criteria listed	>0.10 fractile (i.e., 10th percentile) for Aβ42 <0.9 fractile (i.e., 90th percentile) for tau	Aβ42 500 ng/L (not age dependent) T-tau 300 ng/L (for age range 21–50) 450 ng/L (for age range 51–70) 500 ng/L (for age range ≥71)
Burkhard et al. (2004)	University Hospital of Geneve	105 (total) 82 (age >50 years)	69, 56–78 (median, interquartile range) 29–96 (range)	61 F 44 M	Historical referral of absence of any CNS or PNS condition, or psychiatric condition, or chronic systemic illness possibly modifying the CSF proteins Face-to-face questionnaire covering the most common neurological symptoms Intake of medication potentially interfering with brain functions Neuropathological findings confirming the absence of any dementia (for 10 autopsy proven cases)	>10th percentile for Aβ42 <90th percentile for tau	Aβ42 150 ng/L, 90% Confidence Interval 90–172 ng/L (for age >49 years) T-tau 385 ng/L, 90% Confidence Interval 332–451 ng/L (for age >49 years)